Electrical busway distribution systems have long been employed in buildings where occasional exposure to dripping water from a leaky roof or water sprayed from a nearby broken pipe or a fire sprinkler system may occur. Busways designed for indoor use are intended for installation in dry locations and therefore do not have a completely sealed enclosure. However, indoor busway enclosures will generally provide adequate protection against occasional exposure to water dripping or spraying except at the joint between two adjacent busway sections where the enclosure does not continuously enclose the bus bars and is therefore susceptible to the ingress of water. In order to protect an indoor busway installation from these occasional exposures to dripping or sprayed water, a continuous drip hood may be installed immediately above the busway to prevent dripping water from falling on the busway enclosure and then running into the joint. Supplementary joint covers have also been used to cover the joint areas of indoor busway. These supplementary covers require that water dams be factory installed at the ends of the busway enclosure to prevent water from entering the joint area. The factory installation process requires that the dams be physical attached to the ends of the enclosure and then caulked with a water resistant sealant to prevent the passage of water between the dam and the enclosure. These dams are susceptible to shipping damage or damage during installation of the busway which could cause the water resistant sealant to separate from the enclosure or dam and thereby allow water to pass into the joint area. In some cases, expensive specially designed outdoor busway systems may be installed. The outdoor busway enclosures and joint covers are designed to prevent the ingress of water when exposed to heavy downpours and rain blown by high winds. In any case the installation is more expensive due to increased material and labor costs.
The most desirable solution is to provide an inexpensive and easily installable system of supplementary water dams and joint covers which may be added to sections of previously assembled or previously installed less expensive indoor busway systems. The supplementary dams and covers providing a water resistant seal which protects the entire busway joint area from the ingress of occasional dripping or sprayed water.